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We generalise Jensen's result on the incompatibility of subcompactness with square. We show that alpha^+-subcompactness of some cardinal less than or equal to alpha precludes square_alpha, but also that square may be forced to hold…

Logic · Mathematics 2014-10-01 Andrew D. Brooke-Taylor , Sy-David Friedman

Given a size-$k$ subset $S$ of a group $G$, how large can the product set $S^n$ be? We study this question, at several layers of refinement, for the infinite dihedral group. First, we give an explicit formula for the maximum size of $S^n$…

Group Theory · Mathematics 2026-03-25 Be'eri Greenfeld , George King , Xiaoxuan Li , Sam Tacheny

The main focus of this paper is on the problem of relating an ideal $I$ in the polynomial ring $\mathbb Q[x_1, \dots, x_n]$ to a corresponding ideal in $\mathbb F_p[x_1,\dots, x_n]$ where $p$ is a prime number; in other words, the…

Commutative Algebra · Mathematics 2019-12-13 John Abbott , Anna Maria Bigatti , Lorenzo Robbiano

We continue our study of Sierpinski-type colourings. In contrast to the prequel paper, we focus here on colourings for ideals stratified by their completeness degree. In particular, improving upon Ulam's theorem and its extension by Hajnal,…

Logic · Mathematics 2023-12-19 Tanmay Inamdar , Assaf Rinot

If $\kappa$ is regular and $2^{<\kappa}\leq\kappa^+$, then the existence of a weakly presaturated ideal on $\kappa^+$ implies $\square^*_\kappa$. This partially answers a question of Foreman and Magidor about the approachability ideal on…

Logic · Mathematics 2020-10-01 Sean Cox , Monroe Eskew

We prove that some natural "outside" property is equivalent (for a first order class) to being stable. For a model, being resplendent is a strengthening of being kappa-saturated. Restricting ourselves to the case kappa > |T| for…

Logic · Mathematics 2022-10-18 Saharon Shelah

J. B. Pendry's "Negative Refraction Makes a Perfect Lens" is analyzed. It appears that several statements may be understood in terms of lens design but not in terms of fundamental behavior of light.

General Physics · Physics 2009-11-07 John Michael Williams

We investigate the class of models of a general dependent theory. We continue math.LO/0702292 in particular investigating so called "decomposition of types"; thesis is that what holds for stable theory and for Th(Q,<) hold for dependent…

Logic · Mathematics 2012-02-28 Saharon Shelah

A space X is kappa-resolvable (resp. almost kappa-resolvable) if it contains kappa dense sets that are pairwise disjoint (resp. almost disjoint over the ideal of nowhere dense subsets of X). Answering a problem raised by Juhasz, Soukup, and…

General Topology · Mathematics 2007-05-23 Istvan Juhasz , Saharon Shelah , Lajos Soukup

We try to build, provably in ZFC, for a first order T a model in which any isomorphism between two Boolean algebras is definable. The problem, compared to [Sh:384], is with pseudo-finite Boolean algebras. A side benefit is that we do not…

Logic · Mathematics 2016-01-15 Saharon Shelah

Modifications of the authors' previously-published, generalized, lumped-element, reflectionless filter topologies are presented which remove the original constraints on the relative values of its prototype parameters. Thus, any transfer…

Instrumentation and Methods for Astrophysics · Physics 2018-07-03 Matthew A. Morgan , Wavley M. Groves , Tod A. Boyd

We determine the large cardinal consistency strength of the existence of a $\lambda$-supercompact cardinal $\kappa$ such that GCH fails at $\lambda$. Indeed, we show that the existence of a $\lambda$-supercompact cardinal $\kappa$ such that…

Logic · Mathematics 2012-07-27 Brent Cody

Negative index of refraction has become an accepted part of transformation optics, which is encountered in transformations that change the orientation of the manifold. Based on this concept, various designs of perfect lenses have been…

Optics · Physics 2009-12-15 L. Bergamin

We show that Kunen's saturated ideal over $\aleph_1$ is not centered. We also evaluate the extent of saturation of Laver's saturated ideal in terms of $(\kappa,\lambda,<\nu)$-saturation.

Logic · Mathematics 2022-07-26 Kenta Tsukuura

Parametric and semiparametric tests of circular reflective symmetry about an unknown central direction are developed that are locally and asymptotically optimal in the Le Cam sense against asymmetric $k$-sine-skewed alternatives. The…

Methodology · Statistics 2020-09-01 Jose Ameijeiras-Alonso , Christophe Ley , Arthur Pewsey , Thomas Verdebout

We explore a general mechanism that allows (1+1)d CFTs to have interesting interface conformal manifolds even in the absence of any continuous internal symmetry or supersymmetry. This is made possible by the breaking of an enhanced…

High Energy Physics - Theory · Physics 2025-05-16 Andrea Antinucci , Christian Copetti , Giovanni Galati , Giovanni Rizi

The widely-accepted theoretical treatment of the electromagnetic boundary problem of evanescent wave transfer at an interface between a normal medium of n=1 and an ideal negative index medium of n=-1 neglects the non-zero induced surface…

Optics · Physics 2013-06-12 Weiguo Yang , Michael A. Fiddy

The article exhibits certain relations between the injective envelope I(A) of a C*-algebra A and the von Neumann algebra generated by a representation lambda of A provided it is injective. More specifically we show that there exist positive…

Operator Algebras · Mathematics 2024-11-14 Ulrich Haag

We introduce the notion of $K$-ideals associated with Kuratowski partitions and we prove that each $\kappa$-complete ideal on a measurable cardinal $\kappa$ can be represented as a $K$-ideal. Moreover, we show some results concerning…

Logic · Mathematics 2017-06-28 Joanna Jureczko , Bogdan Węglorz

A cardinal kappa is countably closed if mu^omega < kappa whenever mu < kappa. Assume that there is no inner model with a Woodin cardinal and that every set has a sharp. Let K be the core model. Assume that kappa is a countably closed…

Logic · Mathematics 2016-09-07 William J. Mitchell , Ernest Schimmerling , John R. Steel